Why we may be in for a long, hot summer

CBC

Anytime temperatures approach 30 C in Metro Vancouver, it's a talker.

And while the thermostat does get close once or twice each summer, this particular heat wave has a lot of added factors. First of all — it's early. Seasonal highs for Vancouver right now are just 20 C.

And the forecast temperatures will likely end up 10 degrees above that this weekend — numbers more reminiscent of July or August.

This heat wave will also be intense. Temperatures will steadily climb right across southern B.C. over the next few days — peaking on Sunday at 30 degrees for the South Coast, and approaching the 40s in the Interior.

Daily temperature records will fall, but so too will many all-time hottest June-day records. It looks like we will a least get close for places like Vancouver (30.6 C), Kelowna (38 C) and Kamloops (39.1 C).

Finally, this heat is just the latest 'extreme' in what has been an incredibly warm and dry year overall. Most of B.C. is coming out of a winter of record low snow packs.

Long range forecast calls for hot summer

This past May was the driest on record for most of the province. So far, just a fraction of June rain has fallen. And in general, temperatures have been above seasonal for weeks on end.

This provides that much more of an impact to our hot weather forecast when it comes to fire danger and drought concerns. After an explosive start to the fire season, and reservoirs dropping at an alarming speed, a dry forecast ramps up the danger, and a hot one means evaporation of any moisture happens at a faster rate.

Now for the 'why'. Our weather story for months has been a persistent high pressure system sitting off our coast. It has not only kept us protected from Pacific rain-makers, but it's also ushered in warmer temperatures.

The driving factor here is warmer than normal sea-surface temperatures over the eastern Pacific. And It's here to stay for the summer thanks to a strengthening El Niño.

This weekend, a slightly different set-up is occurring. The core of our heat is actually coming from the southwestern U.S. states. It's being driven north by a strong high pressure system sitting over Arizona — directing hot, dry air that forms over the desert up into the Pacific Northwest.

So when will B.C. catch a break? It's generally a hot and dry forecast through the weekend and through next week. But there are a few mini- breaks to watch out for.

Small chance of a break

Afternoon thunderstorms are possible right across B.C., including Vancouver both Saturday and Sunday. They will be isolated if they happen, and will also bring the risk for fire-starting lightning. There may also be some quick rain Monday night into Tuesday before the forecast dries up again. And it will.

Long range outlooks for the West Coast continue to show a strong likelihood the heat will continue. Your best bet this weekend may be the beach. Temperatures will be a good three to four degrees cooler than even a few blocks inland.